The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of all of Earth's volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism Network.

Note: Many news agencies do not archive the articles they post on the Internet, and therefore the links to some sources may not be active. To obtain information about the cited articles that are no longer available on the Internet contact the source.

KVERT reported that during 15-22 October seismic activity from Kliuchevskoi was above background levels and two lava flows from the summit crater traveled down the SW and W flanks. Satellite imagery analyses showed a large and intense daily thermal anomaly over the volcano and ash plumes that drifted 420 km E and SE. Strombolian activity, observed every day, ejected material 250 m above the crater. Ash plumes rose to an altitude of 7.5 km (24,600 ft) a.s.l. during 20-21 October and to an altitude of 6.5 km (21,300 ft) a.s.l. on the other days during 15-22 October. The Aviation Color Code level remained at Orange.

On 23 October, KVERT reported increased seismicity, characterized by an abrupt change in volcanic tremor, and explosive activity. Ash plumes rose to altitudes of 8-9 km (26,200-29,500 ft) a.s.l. and drifted more than 300 km N. The Aviation Color Code level was raised to Red. The next day the magnitude of tremor decreased and gas-and-steam plumes rose to an altitude of 6.5 km (21,300 ft) a.s.l. Gas-and-steam plumes possibly containing ash drifted SE. The Aviation Color Code level was lowered to Orange. On 25 October, the magnitude of volcanic tremor fluctuated. Ash plumes rose to altitudes of 8-8.5 km (26,200-27,900 ft) a.s.l. and drifted SE. The Aviation Color Code level was again raised to Red. The VAAC reported on 26 October that ash was observed in satellite imagery.

Geologic Summary. Kliuchevskoi is Kamchatka's highest and most active volcano. Since its origin about 7,000 years ago, the beautifully symmetrical, 4,835-m-high basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. More than 100 flank eruptions, mostly on the NE and SE flanks of the conical volcano between 500 m and 3,600 m elevation, have occurred during the past 3,000 years. The morphology of its 700-m-wide summit crater has been frequently modified by historical eruptions, which have been recorded since the late-17th century. Historical eruptions have originated primarily from the summit crater, but have also included major explosive and effusive events from flank craters.

CVGHM reported that from the end of September to 20 October the rate of inflation at Merapi was 0.6 cm per day. On 21 October the rate increased to 10.5 cm per day, and incidents of incandescence from the lava dome increased. CVGHM raised the Alert Level to 3 (on a scale of 1-4). The rate of inflation increased sharply on 24 October to a rate of 42 cm per day. The next day, CVGHM raised the Alert Level to 4, and recommended immediate evacuation for several communities (news reports estimated 11,000-19,000 people) within a 10-km radius.

An eruption began at about 1700 on 26 October that was characterized by explosions along with pyroclastic flows that traveled WSW and SE. CVGHM reported that multiple pyroclastic flows occurred until 1854, when the pyroclastic flow activity started to subside. Most of the pyroclastic flows lasted 2 to 9 minutes, except for two that lasted 33 minutes each. Booming noises were heard, and incandescence from the crater was seen from the Selo observation post to the N. An ash plume was also observed rising 1.5 km above the crater.

According to news articles, officials noted that about 15,000 people had not yet evacuated, even though several minor eruptions had already occurred prior to 26 October. Reports on 27 October noted that about 25 people died and several were injured.

Geologic Summary. Merapi, one of Indonesia's most active volcanoes, lies in one of the world's most densely populated areas and dominates the landscape immediately N of the major city of Yogyakarta. The steep-sided modern Merapi edifice, its upper part unvegetated due to frequent eruptive activity, was constructed to the SW of an arcuate scarp cutting the eroded older Batulawang volcano. Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated and inhabited lands on the volcano's western-to-southern flanks and caused many fatalities during historical time. The volcano is the object of extensive monitoring efforts by the Merapi Volcano Observatory (MVO).

OVPDLF reported that an eruption from Piton de la Fournaise that began on 14 October from a fissure near the Château Fort crater, about 1.5 km SE of the Dolomieu crater rim, continued during 19-25 October. On 19 October, explosive and degassing activity from vents along the fissure increased, but was still below the intensity noted at the beginning of the eruption. During 20-21 October small lava fountains fed lava flows that traveled as far as 2 km E and SE. Decreased gas emissions were concentrated to the S and W of the fissure. During 22-24 October fountains and gas emissions originated from one vent, and lava traveled ESE. Gas emissions decreased significantly.

Geologic Summary. Massive Piton de la Fournaise shield volcano on the island of Réunion is one of the world's most active volcanoes. Most historical eruptions have originated from the summit and flanks of a 400-m-high lava shield, Dolomieu, that has grown within the youngest of three large calderas. This depression is 8 km wide and is breached to below sea level on the eastern side. More than 150 eruptions, most of which have produced fluid basaltic lava flows within the caldera, have been documented since the 17th century. The volcano is monitored by the Piton de la Fournaise Volcano Observatory, one of several operated by the Institut de Physique du Globe de Paris.

Online Public Information File

Viewers with disabilities can get assistance accessing this station's FCC Public Inspection File by contacting the station with the information listed below. Questions or concerns relating to the accessibility of the FCC's online public file system should be directed to the FCC at 888-225-5322, 888-835-5322 (TTY), or fccinfo@fcc.gov.